Mobile communications systems are made up of a plurality of cells or cell sectors. Each cell or cell sector provides a radio communications center through which a mobile station establishes a call or other communications session with another mobile station or a terminal connected to either a circuit-switched network (e.g., public-switched telephone network or PSTN) or a packet-switched data network. Each cell or cell sector includes a base station (or access point) and a base station controller (or radio network controller) to enable communications with mobile stations in the cell or cell sector.
Wireless networks are capable of carrying both circuit-switched and packet-switched traffic (e.g., voice traffic, data traffic, etc.). Examples of wireless networks that support communication of packet-switched traffic include those that operate according to the CDMA 2000 family of standards. The first phase of CDMA 2000 is referred to as 1xRTT (also referred to as 3G1X or 1X), which is designed to increase voice capacity as well as to support data transmission speeds that are faster than typically available. In addition, for even higher data rates, a 1xEV-DO wireless technology has been developed, defined as TIA/EIA/IS-856, “CDMA 2000, High Rate Packet Data Air Interface Specification,” which is adopted by the TIA. 1xEV-DO provides relatively high data transfer rates over the air interface between mobile stations and base stations.
Recently, there has been an increase in the use of enterprise and residential wireless local area networks (WLANs). A WLAN refers to a local area network that mobile stations can access wirelessly. A WLAN is a private network, either owned by an organization or municipality (enterprise) or by an individual. A WLAN is usually secured such that only authorized users are allowed to use the WLAN. A WLAN differs from a public cellular wireless network in that the WLAN is limited for use by users of a specific enterprise or a group, whereas the public cellular wireless network is for general use of subscribers of the cellular wireless network. Examples of standards that define WLANs include IEEE (Institute of Electrical and Electronic Engineers) 802.11, 802.11a, 802.11b, 802.11g, Bluetooth, WiMAX (Worldwide Interoperability for Microwave Access), 802.16, and so forth.
Conventionally, mechanisms have not been provided to enable efficient handoffs from a public cellular wireless network, such as a CDMA 2000 network, to a WLAN, since the cellular wireless network and WLAN operate according to different technologies.